1. Field of the Invention
This invention concerns a high-frequency induction heating device and a device and method for using the high-frequency induction heating device to pyrolyze organic compounds. Specifically, this invention belongs to an art by which substances containing harmful compounds such as organohalogen compounds and other hazardous substance are decomposed in a gas phase by high-frequency induction heating.
2. Description of Related Arts
Organohalogen compounds, which contain chlorine, bromine, or other halogens, include many compounds that are designated as specified chemical substances or designated chemicals and also include many compounds that are causative agents of environmental problems. Representative examples include halogen-substituted aromatic organic compounds, such as dioxins, polychlorinated biphenyls, chlorobenzene, etc., and aliphatic organohalogen compounds, such as tetrachloroethylene, trichloroethylene, dichloromethane, carbon tetrachloride, 1,2-dichloroethylene, 1,1-dichloroethylene, cis-1,2-dichloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,3-dichloro-propene, etc.
These organohalogen compounds exist in various forms, i.e., solid, liquid, and gas forms.
For example, polychlorinated biphenyls (hereinafter referred to as xe2x80x9cPCBsxe2x80x9d), due to being highly resistant and chemically stable against acids and bases, extremely stable thermally, excellent in electric insulating properties, wide in the form of existence from liquid to solid, etc., have been used widely and in large amounts in numerous applications as insulating oils for transformers, capacitors, etc., plasticizers for electric cables, etc., and thermal media for a variety of processes in various chemical industries.
However, it has been found that hazardous substances are generated and environmental pollution is caused when PCBs and substances containing PCBs are combusted and that hazardous substances, originating from PCB""s, become accumulated in human bodies by biological concentration through the food chain, especially through fishes, shellfishes, and other marine products. The production of PCBs was thus prohibited in 1972. Though problems of direct pollution due to the manufacture, etc. of PCBs were thus avoided, since PCBs have been used in a wide variety of uses due to their high degree of general usability and are difficult to decompose, the treatment and disposal of PCBs and substances containing PCBs have now become new environmental problems.
That is, if ordinary incineration treatment is performed to treat and dispose of PCBs and substances containing PCBs, dioxin and other hazardous substances are generated due to the low incineration temperature and these hazardous substances become discharged into the atmosphere along with flue gas, thereby causing further air pollution. On the other hand, if landfill disposal is performed, since PCBs have the properties of being excellent in stability and extremely difficult to decompose, the PCBs become eluted into the soil to give rise to soil, river, and marine pollution.
PCBs and products containing PCBs therefore could not be treated or disposed readily and the actual circumstances are such that PCBs and/or substances containing PCBs are simply stored upon being recovered by municipalities, etc.
Under such circumstances, various methods of treating PCBs are being examined. Representative decomposition treatment methods include high temperature incineration treatment methods, decomposition by enzymes and bacteria, treatment by chemicals (alkaline decomposition methods), etc., and among these, high-temperature incineration methods, with which PCBs are subject to incineration treatment at high temperature, were the most effective methods.
However, even with high-temperature incineration methods, there were problems that required improvement, such as the degradation of the furnace by the chlorine that is generated when PCBs are decomposed, the difficulty of furnace body management due to the requirement of high temperature (for example, 1600xc2x0 C. or more) for treatment, the containing of large amounts of undecomposed PCBs in the incineration residue in some cases due to the incineration heat not being transmitted completely to the treated object, the generation of coplanar PCBs, dioxin, and other new hazardous substances in some cases by low temperature incineration caused by the inability to perform swift temperature control upon lowering of the incineration temperature due to poor control response to incineration temperature, etc.
Also, in the case of treatment of PCBs contained inside a container, such as in the case of a transformer, capacitor, etc., the PCBs could not be treated unless the PCBs were taken out of the transformer, capacitor, etc., and there were problems of contamination of workers during the work of taking out the PCBs and problems of treatment of PCBs remaining inside a transformer or capacitor after taking out the PCBs.
Also, a high-temperature incineration furnace is an extremely expensive device and a vast amount of space is required for the installation of a high-temperature incineration furnace. A high-temperature incineration furnace is also a device that takes an extremely large amount of time for the interior of the furnace to reach a desired temperature (that is, slow in startup) and takes an extremely large amount of time for the internal temperature to drop to ordinary temperature after heating has been stopped.
Thus in the case where organohalogen compounds are to be decomposed using a high-temperature incineration furnace, a large amount of the treated object had to be treated in a batch and the treatment of organohalogen compounds in a small-scale facility accompanied extreme difficulties. There were thus demands for a decomposition device and a decomposition method for organohalogen compounds with which heating to a predetermined temperature could be accomplished within an extremely short amount of time and which are compatible with equipment from comparatively small-scale equipment to large-scale equipment.
Also, these organohalogen compounds are contained in solids, liquids, and gases, and there were thus demands for a method of decomposing these organic compounds safely and without fail by practically the same operation method.
Furthermore, various organic compounds besides organohalogen compounds are causative agents of environmental pollution. There were thus demands for a pyrolysis device and pyrolysis method by which decomposition treatment of solids, liquids, and gases containing, for example, malodorous substances, such as indole, skatole, captans, etc., various environmental hormones, formaldehyde and other causative agents of sick house syndrome, waste oil, waste molasses, etc., can be carried out in a unified manner.
That is, there were strong demands for an organic compound pyrolysis device and pyrolysis method by which objects to be treated that contain organic compounds can be pyrolyzed and rendered harmless with a single device, regardless of the form (gas, liquid, or solid) of the organic compounds to be treated and the treated objects containing these organic compounds.
This invention provides a high frequency induction heating device suitable for use in a device for decomposing an organic compound, which heats and decomposes organic compounds in at least one pyrolysis zone each comprising at least one high-frequency induction heating device.
By the use of a high-frequency induction heating device, the degree of freedom of design of the pyrolysis zone is increased. In particular, the high-frequency induction heating device used in this invention can heat to a predetermined temperature, such as 1600xc2x0 C., in an extremely short period, such as in 1 second or less, and moreover, enables the heating zone itself to be provided within a small space.
With this invention, by providing a means for gasifying solids and/or liquids at a stage upstream the heating zone, organohalogen compounds contained in the solids and/or liquids can be subject to pyrolysis treatment.
Thus a specific embodiment of this invention may have an arrangement with a gasifying device, for gasification of liquids or solids containing organic compounds, provided at a stage upstream the pyrolysis zone.
Such an arrangement enables decomposition treatment of organic compounds contained in gases, liquids, and solids to be performed with a single device. That is, treatment of organic compounds contained in a gas can be performed by the bypassing of the above mentioned gasifying device.
Also in the case where the organic compounds to be treated are organohalogen compounds that are comparatively difficult to decompose (for example, PCBs), this invention""s device may be provided with two or more pyrolysis zones.
In this case, a preheating zone may be provided at a stage upstream a pyrolysis zone, which comprises this invention""s high-frequency induction heating device. Additionally or alternatively, a pyrolysis zone, which makes use of radiant heat or comprises another high-frequency induction heating device, may be provided at a stage downstream the pyrolysis zone comprising this invention""s high-frequency induction heating device. Also, it is also possible to provide a plurality of high-frequency induction heating devices within one pyrolysis zone
According to specific embodiments of the present invention, there provide the following novel high-frequency induction heating devices.
1. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolysis part;
said pyrolysis part comprising a cylindrical body both ends of which are sealed, slits which communicate the interior with the exterior of said cylindrical body provided on the outer surface of said cylindrical body, and a communication pores to be communicated with an introduction tube which introduces said gas to be treated into the interior of said cylindrical body.
2. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolysis part;
said pyrolysis part comprising a cylindrical body which introduces the gas provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
3. The high-frequency induction heating device as set forth in Item 1, wherein said cylindrical body is provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
4. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolisis part;
said pyrolysis part having a heating element having a plurality of through holes along the inside of the outer circumference of the diameter direction thereof and ceramic pipes inserted within said plurality of through holes and supported by pipe supporting plates accommodated therein.
5 The high-frequency induction heating device as set forth in Item 4, wherein said pyrolysis part has pressure reducing means for reducing the pressure of the body.
6 The high-frequency induction heating device as set forth in Item 4, wherein said pyrolysis part has compressing means for compressing the body by an inert gas.
7. The high-frequency induction heating device as set forth in Item 4, wherein said pipe supporting plate has a guide member for introducing a gas to be treated into said ceramic pipe.
8. The high-frequency induction heating device as set forth in Item 7, wherein said ceramic pipe is made of at least one member selected from the group consisting of silicon carbide and alumina.
9. The high-frequency induction heating device as set forth in Item 8, wherein step part to be fit to spacers are provided on both ends of said heating element.
10. The high-frequency induction heating device as set forth in Item 9, wherein said spacer comprises non-dielectric material and is formed from a flange having the plurality of through holes and cylindrical body.